In the race to be the first to reach the ACID3 reference rendering, Opera's software leads now with 98%, closely following by Safari with 96% and Firefox 3 beta 4 with 71%.
Update: 03/26 21:21 GMT by Z : Opera is now at 100%, apparently, with Safari close behind at 98%. Update: 03/27 by J : Public build r31356 of WebKit (Safari's rendering engine) is at 100%.
Browser wars, but fighting each other for the best compliance? Awesome beyond words! Microsoft take note.